Add driver for NXP LPC18xx/43xx Clock Generation Unit (CGU). The CGU
contains several clock generators and output stages that route the
clocks either directly to peripherals or to a Clock Control Unit
(CCU).
Signed-off-by: NJoachim Eastwood <manabian@gmail.com>
Signed-off-by: NMichael Turquette <mturquette@baylibre.com>